The present invention relates to an information read and/or write apparatus and method for detecting wobbles with high accuracy in reading/writing information from/on a wobbled information read and/or write medium such as DVDs, and to an information storage medium on which information for implementing the information read and/or write method is stored.
The present application claims priority from Japanese Application No. 2000-388609, the disclosure of which is incorporated herein by reference for all purposes.
Digital versatile disks or digital video disks (DVDs) have been developed as an information read and/or write medium which enables high-density storage of information. In addition to read-only DVDs such as DVD-Videos or DVD-ROMs, writable. DVDs such as DVD-Rs and rewritable DVDs such as DVD-RWs have also been developed, with which the DVD family has been filled out.
However, for users who use such DVDs of many types, it is inconvenient to buy a purpose-built information read and/or write apparatus for use with each type of the DVDs. Accordingly, it has become more demanding to develop a versatile information read and/or write apparatus which can be used with each of those of the DVD family irrespective of their types.
Even such DVDs which belong to the same DVD family have each a different physical structure for storing information thereon and different physical and logical data structures. Accordingly, to read or write information on a DVD, an information read and/or write apparatus has to first determine whether the DVD is wobbled or non-wobbled so that the information can be read or written properly on the DVD in accordance with the type of the DVD. (The information read and/or write apparatus used herein is a generic name for an information read-only apparatus, an information write-only apparatus, and an apparatus which enables reading and writing information.)
Furthermore, suppose such a DVD having contents stored thereon is detected which are not allowed to be copied. In this case, from the viewpoint of copyright protection, it is necessary to determine the type of the DVD in order to prevent the apparatus from reading information on the DVD having contents illegally copied.
However, there has been a problem of the information read and/or write medium which is caused by variations in manufacturing of the DVD or a curved read and/or write surface. There has also been another problem of the information read and/or write apparatus which is caused by the optical pickup, incorporated in the information read and/or write apparatus, having an individual difference and by the aging of the pickup or by the aging of an electronic component which is incorporated in the signal processing circuit. These problems have made it difficult to determine the presence or absence of wobbles with high accuracy. That is, even when an information read and/or write apparatus has been provided with the optimum factory condition for setting and shipping, it has been difficult to prevent the degradation in accuracy of determining wobbles under an expected environment after the shipping of the information read and/or write apparatus.
The present invention has been developed in view of these conventional problems. It is therefore an object of the present invention to provide an information read and/or write apparatus and method for enabling a highly accurate determination of the presence or absence of wobbles. It is another object of the present invention to provide an information read and/or write medium having information stored thereon for enabling a highly accurate determination of the presence or absence of wobbles.
According to a first aspect of the invention, there is provided an information read and/or write apparatus having a function for distinguishing between an information read and/or write medium having a wobbled track and an information read and/or write medium having a non-wobbled track, comprising: a light-receiving device for receiving a light beam reflected on said information read and/or write medium; signal generator device for generating a signal characteristic of a read and/or write surface of said information read and/or write medium in accordance with an output signal delivered by said light-receiving device; sensor device for detecting the characteristic information of said read and/or write surface in accordance with the signal delivered by said signal generator device and for determining a detection rate of the characteristic information per a prescribed detection time period; determination device for determining presence or absence of said wobbled track on said information read and/or write medium in accordance with said detection rate; and control device for controlling detection sensitivity to detect said characteristic information by adjusting a detection sensitivity parameter when said determination device has provided a determination in error.
According to a second aspect of the invention, there is provided an information read and/or write apparatus having a function for distinguishing between an information read and/or write medium having a wobbled track and an information read and/or write medium having a non-wobbled track, comprising: a light-receiving device for receiving a light beam reflected on said information read and/or write medium; signal generator device for generating a signal characteristic of a read and/or write surface of said information read and/or write medium in accordance with an output signal delivered by said light-receiving device; sensor device for detecting the characteristic information of said read and/or write surface in accordance with the signal delivered by said signal generator device and for determining a detection rate of the characteristic information per a prescribed detection time period; and determination device for comparing a plurality of detection rates determined by said sensor device with a prescribed threshold to find a determination rate or a ratio of a detection rate count exceeding said threshold to a detection rate count to be compared with and then determine the presence or absence of said wobbled track on the information read and/or write medium in accordance with a determination of whether said determination rate is greater than the prescribed determination threshold, and for adjusting said determination threshold when said determination device has provided a determination in error. In particular, the determination threshold is set at a value for distinguishing between said information read and/or write medium having said wobbled track and said information read and/or write medium having said non-wobbled track.
According to a third aspect of the invention, there is provided an information read and/or write apparatus having a function for distinguishing between an information read and/or write medium having a wobbled track and an information read and/or write medium having a non-wobbled track, comprising: a light-receiving device for receiving a light beam reflected on said information read and/or write medium; signal generator device for generating a signal characteristic of a read and/or write surface of said information read and/or write medium in accordance with an output signal delivered by said light-receiving device; sensor device for detecting the characteristic information of said read and/or write surface in accordance with the signal delivered by said signal generator device and for determining a detection rate of the characteristic information per a prescribed detection time period; determination device for determining presence or absence of wobbles on said information read and/or write medium in accordance with said detection rate; control device for controlling detection sensitivity to detect said characteristic information by adjusting a detection sensitivity parameter when said determination device has provided a determination in error; and determination device for comparing a plurality of detection rates determined by said sensor device with a prescribed threshold to find a determination rate or a ratio of a detection rate count exceeding said threshold to a detection rate count to be compared with and then determine that the information read and/or write medium has said wobbled track when said determination rate is greater than the prescribed determination threshold.
According to a fourth aspect of the invention, there is provided an information read and/or write method for distinguishing between an information read and/or write medium having a wobbled track and an information read and/or write medium having a non-wobbled track, comprising the steps of: generating a signal characteristic of a read and/or write surface of said information read and/or write medium in accordance with a light beam reflected on said information read and/or write medium; detecting the characteristic information of said read and/or write surface in accordance with the generated signal to determine a detection rate of the characteristic information per a prescribed detection time period; determining presence or absence of said wobbled track on said information read and/or write medium in accordance with said detection rate; and controlling detection sensitivity to detect said characteristic information by adjusting a detection sensitivity parameter when a determination has been provided in error in said step of determining the presence or absence of said wobbled track.
According to a fifth aspect of the invention, there is provided an information read and/or write method for distinguishing between an information read and/or write medium having a wobbled track and an information read and/or write medium having a non-wobbled track, comprising the steps of: generating a signal characteristic of a read and/or write surface of said information read and/or write medium in accordance with a light beam reflected on said information read and/or write medium; detecting the characteristic information of said read and/or write surface in accordance with the generated signal to determine a detection rate of the characteristic information per a prescribed detection time period; and comparing said plurality of detection rates with a prescribed threshold to find a determination rate or a ratio of a detection rate count exceeding said threshold to a detection rate count to be compared with and then determine the presence or absence of said wobbled track on the information read and/or write medium in accordance with a determination of whether said determination rate is greater than a prescribed determination threshold, and adjust said determination threshold when said determination has been provided in error. In particular, the determination threshold is set at a value for distinguishing between said information read and/or write medium having said wobbled track and said information read and/or write medium having said non-wobbled-track.
According to a sixth aspect of the invention, there is provided an information read and/or write method for distinguishing between an information read and/or write medium having a wobbled track and an information read and/or write medium having a non-wobbled track, comprising the steps of: generating a signal characteristic of a read and/or write surface of said information read and/or write medium in accordance with a light beam reflected on said information read and/or write medium; detecting the characteristic information of said read and/or write surface in accordance with the generated signal to determine a detection rate of the characteristic information per a prescribed detection time period; determining presence or absence of said wobbled track on said information read and/or write medium in accordance with said detection rate; controlling detection sensitivity to detect said characteristic information by adjusting a detection sensitivity parameter when a determination has been provided in error in said step of determining the presence or absence of said wobbled track; and comparing said plurality of detection rates with a prescribed threshold to find a determination rate or a ratio of a detection rate count exceeding said threshold to a detection rate count to be compared with and then determine that the information read and/or write medium has said wobbled track when said determination rate is greater than the prescribed determination threshold.
According to a seventh aspect of the invention, there is provided a computer data signal embodied in a carrier wave and representing a series of instructions which cause a computer to perform steps to distinguish between an information read and/or write medium having a wobbled track and an information read and/or write medium having a non-wobbled track, said program information comprising the steps of: generating a signal characteristic of a read and/or write surface in accordance with a light beam reflected on said information read and/or write medium to be determined; detecting the characteristic information of said read and/or write surface in accordance with the generated signal to determine a detection rate of the characteristic information per a prescribed detection time period; determining presence or absence of said wobbled track on said information read and/or write medium in accordance with said detection rate, and controlling detection sensitivity to detect said characteristic information by adjusting a detection sensitivity parameter when a determination has been provided in error in said step of determining the presence or absence of said wobbled track.
According to an eighth aspect of the invention, there is provided a computer data signal embodied in a carrier wave and representing a series of instructions which cause a computer to perform steps to distinguish between an information read and/or write medium having a wobbled track and an information read and/or write medium having a non-wobbled track, said program information comprising the steps of: generating a signal characteristic of a read and/or write surface of said information read and/or write medium in accordance with a light beam reflected on said information read and/or write medium to be determined; detecting the characteristic information of said read and/or write surface in accordance with the generated signal to determine a detection rate of the characteristic information per a prescribed detection time period; and comparing said plurality of detection rates with a prescribed threshold to find a determination rate or a ratio of a detection rate count exceeding said threshold to a detection rate count to be compared with and then determine the presence or absence of said wobbled track on the information read and/or write medium in accordance with a determination of whether said determination rate is greater than a prescribed determination threshold, and adjust said determination threshold when said determination has been provided in error. In particular, the determination threshold is set at a value for distinguishing between said information read and/or write medium having said wobbled track and said information read and/or write medium having said non-wobbled track.
According to a ninth aspect of the invention, there is provided a computer data signal embodied in a carrier wave and representing a series of instructions which cause a computer to perform steps to distinguish between an information read and/or write medium having a wobbled track and an information read and/or write medium having a non-wobbled track, said program information comprising the steps of generating a signal characteristic of a read and/or write surface of a information read and/or write medium of said information read and/or write medium in accordance with a light beam reflected on said information read and/or write medium to be determined; detecting the characteristic information of said read and/or write surface in accordance with the generated signal to determine a detection rate of the characteristic information per a prescribed detection time period; determining presence or absence of said wobbled track on said information read and/or write medium in accordance with said detection rate; controlling detection sensitivity to detect said characteristic information by adjusting a detection sensitivity parameter when a determination has been provided in error in said step of determining the presence or absence of said wobbled track; and comparing said plurality of detection rates with a prescribed threshold to find a determination rate or a ratio of a detection rate count exceeding said threshold to a detection rate count to be compared with and then determine that the information read and/or write medium has said wobbled track when said determination rate is greater than the prescribed determination threshold.
The invention according to the first, fourth, and seventh aspects is adapted to generate a signal characteristic of the read and/or write surface in accordance with a light beam reflected on the information read and/or write medium to be determined. However, it has not yet been determined whether the signal derives from a wobbled or a non-wobbled information read and/or write medium. Therefore, the detection rate of the characteristic information contained in the signal per a prescribed detection time period is further determined. When the detection rate has become less than the prescribed detection sensitivity threshold, a detection sensitivity parameter is adjusted. In this case, the parameter is adjusted such that the detection rate can well represent the information regarding the presence or absence of wobbles to determine the presence or absence of wobbles in accordance with the value of the detection rate.
The invention according to the second, fifth, and eighth aspects is adapted to generate a signal characteristic of the read and/or write surface in accordance with a light beam reflected on the information read and/or write medium to be determined. However, it has not yet been determined whether the signal derives from a wobbled or a non-wobbled information read and/or write medium. Therefore, the detection rate of the characteristic information contained in the signal per a prescribed detection time period is further determined. Furthermore, a plurality of detection rates are compared with a prescribed threshold to find a determination rate or a ratio of a detection rate count to be compared with to a detection rate count exceeding the threshold. Then, the presence or absence of wobbles on the information read and/or write medium is determined in accordance with a determination of whether the determination rate is greater than a prescribed determination threshold. In addition to this, the determination threshold is adjusted when the determination has been provided in error. This improves the accuracy of determining the presence or absence of wobbles.
The, invention according to the third, sixth, and ninth aspects is adapted to generate a signal characteristic of the read and/or write surface in accordance with a light beam reflected on the information read and/or write medium to be determined. However, it has not yet been determined whether the signal derives from a wobbled or a non-wobbled information read and/or write medium. Therefore, the detection rate of the characteristic information contained in the signal per a prescribed detection time period is further determined. Then, the presence or absence of wobbles is determined in accordance with the detection rate. When the determination has been provided in error, the detection sensitivity parameter is adjusted such that the detection rate can thereby well represent the information regarding the presence or absence of wobbles. Furthermore, a plurality of detection rates are compared with a prescribed threshold to find a determination rate or a ratio of a detection rate count to be compared with to a detection rate count exceeding the threshold. When the determination rate is greater than the prescribed determination threshold, it is determined that the information read and/or write medium is wobbled. On the other hand, when the determination rate is less than the prescribed determination threshold, the determination threshold is adjusted to thereby improve the accuracy of determining the presence or absence of wobbles.